Income Inequality Plays Out in Cardiac Arrest Ambulance Response

Response slower in the poorest neighborhoods, study finds

Ambulance transfer times are another disadvantage for the poorest neighborhoods, according to a study showing longer times to get out-of-hospital cardiac arrest patients to the hospital than in the richest neighborhoods.

The average response time from emergency medical services (EMS) dispatch to arrival at the destination hospital was 37.5 minutes in the top quartile of zip codes by income, as opposed to 43.0 minutes in the poorest quartile in 2014, reported the team led by Renee Hsia, MD, of the University of California San Francisco, in a paper published online in JAMA Network Open.

Total EMS time remained 10% higher in the poorest zip codes, taking an extra 3.8 minutes after adjusting for time of day, day of week, and urban areas (P<0.001). Compared with the highest-income areas:

Response time was 4% longer (0.3 minutes)

On-scene time was 15% longer (2.8 minutes)

Transport time was 6% longer (0.6 minutes)

The observed on-scene delays might have something to do with the challenges of reaching low-income patients in high-rise buildings in urban areas, establishing scene safety, and communicating with language barriers, the authors suggested.

"Our findings are particularly concerning given the time sensitivity of conditions like cardiac arrest in which the heart has ceased functioning and immediate medical care is required to restore function and circulation. In fact, a recent study showed that even a 4.4-minute delay is associated with a 13% increase in 30-day mortality," the group wrote.

EMS responses times in neighborhoods with zip codes in the lowest quintile by income were less likely to meet national benchmarks -- for example, 72.4% of these areas met the 8-minute threshold (vs 78.1% for the richest zip codes, P<0.001).

Out-of-hospital cardiac arrest patients were more likely to be white and male in the highest-income areas, Hsia's group reported. The lowest-income areas had more Medicaid patients.

Data used in their study came from the U.S. National Emergency Medical Services Information System, which included 63,600 cardiac arrest patients who were transported by EMS to the hospital in 2014. The registry covered 46 states.

People in the highest-income areas made up the majority of these ambulance pickups (59.0%); and just 12.9% were in low-income zip codes.

The investigators came up with several hypotheses for the disparity in ambulance times, including the increasing number of hospitals, emergency departments, and private ambulance company shutdowns.

"The repercussions of the loss of these services may be particularly detrimental in low-income communities, which rely more heavily on prehospital care and have a higher increased incidence of severe, life-threatening illnesses," according to them.

"Simultaneously, the new, shifting landscape to privately owned ambulance companies may lead to a greater focus on profitability over public need, which could drive more companies to serve wealthier neighborhoods, potentially increasing total EMS time, because poorer neighborhoods would have fewer ambulances and personnel to go around," Hsia and colleagues added.

Another explanation may be that rich people are more likely to live where taxes are high and public services are of high quality, which pushes low-income households to locations with relatively lower-quality public services, according to economist Andrew Friedson, PhD, of University of Colorado Denver.

In an accompanying editorial, he highlighted the fact that the data came from 2014, the first full year under the Affordable Care Act (ACA).

The study "may actually be detecting disparities in ambulance system congestion owing to differences in levels of ACA insurance expansion, as opposed to an effect truly driven by income disparities. In this case, policy might be most effective if aimed at ambulance congestion, perhaps by curbing unnecessary patient use of emergency transport," Friedson said.

It would have been a good idea to control for this, he suggested, adding that 2014 was also the year when Uber and other ridesharing apps were proliferating quickly, which might have affected ambulance response times in certain neighborhoods.

Ultimately, EMS transport inequality will likely require more than a single policy approach to be fixed, the editorialist wrote.

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